Fluid pressure regulator responsive to angular velocity and acceleration



June 1954 s. l. GABRIELSON ETAL 2,681,071

FLUID PRESSURE REGULATOR RESPONSIVE TO ANGULAR VELOCITY AND ACCELERATIONFiled Dec. 24, 1948 Fig.1.

Ihvntors: Samuel LGabridson,

Jacqb W. Mc b lanfy,

Patented June 15, 1954 UNITED STATES PATENT OFFICE FLUID PRESSUREREGULATOR RESPONSIVE TO ANGULAR VELOCITY AND ACCELERA- TION ApplicationDecember 24, 1948, Serial No. 67,212

. 3 Claims.

This invention relates to an improved clutch control for washingmachines of the type in which the clothe are washed and spin-dried inthe same basket, and particularly to a hydraulic fluid regulator for aclutch control.

A popular type of such washing machines includes a tub within which abasket is mounted for rotation. An agitator or other mechanical washingdevice in the tub imparts motion to the clothes within the washingliquid. By means of a motor and suitable drive gearing, the agitator isoscillated during washing and rinsing periods, and after the final rinseand drain, the basket is rapidly spun in order to extract the water fromthe clothes by centrifugal action. Because the weight of clothes and thewater contained therein may be substantial the motor is subjected to arelatively heavy load at the commencement of the basket spinning phaseof operation.

Torque responsive means have heretofore been provided for disengagingthe drive clutch to prevent overloading the motor. However, it has beenfound that the motor may stall before the torque responsive meansbecomes effective and the power line to the motor may thereupon becomeoverloaded beyond the capacity of the line fuses. Another objection tothe torque responsive clutch is that low line voltage may cause themotor to stall under the initial load. This condition arises mostfrequently in residential installations in which a refrigerator, iron,or similar appliances may be on the washing machine circuit.

The present invention provide a clutch control which is responsive tomotor speed rather than generated torque, including an improvedcentrifugally operated control element for the clutch. This element issuitably mounted on a rotatable clutch plate to be responsive totangential inertia forces, as well as centrifugal forces, and in such amanner that tangential inertia forces during acceleration anddeceleration have an independent controlling effect tending to dampenthe reaction of the element to changes in the rotational speed of theclutch plate. Consequently, the tendency of the control element to huntor cycle is minimized. This control element causes the basket clutch toautomatically disengage when the motor speed drops to a predeterminedpoint, preferably suitably above the motor stall point, so that themotor will not remain under load until it stalls. For example, if thebasket load is such that motor speed falls toward the danger level, thecontrol will operate to disengage the clutch-at least to the extent ofpermitting slip-before the motor is overloaded. In extreme cases theclutch members may rapidly engage and disengage several times before apermanent clutch closure is effected. Reasonable drops in line voltagedo not adversely affect the operation of the device inasmuch as theclutch engagement is dependent upon motor speed rather than on relativetorque requirements.

It is therefore an object of the invention to provide an improvedcentrifugally operated speed responsive clutch control for washingmachines of the single basket, spin-dry type.

It is a more specific object of the invention to provide a speedresponsive control for a washing machine in which the reaction of thecontrol element to speed changes is damped by its tangential inertia.

It is still a further object of the invention to provide a clutchcontrol which is simple and inexpensive to manufacture and will operateover long periods of time without failure.

These and other features and advantages of the invention will beapparent in the following detailed description of a typical embodiment,with reference to the accompanying drawing, in which: Fig. 1 is avertical section taken through the motor and clutch assembly of aconventional washing machine, and showing the drive gear casing onlyfragmentarily; Fig. 2 is a plan section taken on the lines 22 of Fig. 1,showing the control elements at rest; and Fig. 3 illustrates the controlelements in clutch-engaged position.

Fig. 1 shows so much of a washing machine motor and driving assembly asis necessary for an understanding of the invention. A housing which issuitably mounted in the washing machine frame (not shown), has an upperportion I0 and a lower portion l I, suitably secured at an intermediateweb structure l2. The housing portion In contains the gear casing I lwithin which is a suitable gear train (a portion of which is shown atI5) for oscillating an agitator or other washing device disposed Withina conventional basket having an axis connected to the gear casing 14 sothat said basket will be rotated as the entire gear casing 14 isrotated. This agitator, basket, and'gear casing arrangement is wellknown in the art, and. has not been detailed herein.

The motor l5 has a stator Il' fixed Within the casing part II. Saidstator has conventional starting and running windings collectivelyidentified by the reference IS. The stator core may have one or more oildrainage passages. 20 extending therethrough and. may also provide foran oil tube 2| for pressure lubrication of the gear train I5 and thebearing member 22 of gear casing M. The motor rotor 23 has a tubularshaft 24 which seats within a bearing 25 provided in a part of thesupporting structure 26 fixed to the bottom wall of the casing H asshown. An eccentric chamber 21 for a conventional vane pump is formed inthe structure 26 beneath shaft 24. A tubular hub 29 integral with orfixed to the end of shaft 24 for rotation therewith drivingly supportsthe pump vanes 28. An axial aperture 3!; in shaft 24 registers with thebore of hub 29 and an opening 3| in a pump chamber cover 32 to afiordcommunication with an oil pressure chamber 33 provided by a dished plate34. A passage 35 through the closure plate 32 affords a second path ofcommunication betwen the pump chamber and the space 33. An outletpassage 36 serves the lubrication duct 2|. The plate 34 has an aperture37 which serves as a seat for a plunger valve 38 which is activated by asolenoid 39. A cup forms an oil sump into which the pump inlet tube 4|reaches. 7

As is known in the art, the operation of a washing machine of the singlebasket wash and dry type includes periods of oscillation of an agitatoror similar washing mechanism, and periods in which the basket is spun athigh speed. During agitation, the basket is held stationary by asuitable friction brake or equivalent; under spin condition, theagitator is released for free movement and will rotate with the basket.Two clutches are provided: one to drive the agitator, and one to couplethe gear casing to the motor to be rotated thereby, the gear casingbeing drivingly connected to the spin basket. The agitator clutch isnormally engaged; the weight of the agitator shaft and its accessoriesis sufficient to hold it in engagement and to return it to engagedposition. The gear casing clutch is normally disengaged; its drivenclutch member is resiliently held in frictional engagement with a fixedbrake shoe.

Oil pressure generated by the pump vanes 28 is used to disengage theagitator clutch and engage the spin basket clutch. As will be presentlyexplained the agitator clutch disengages shortly before the basketclutch is engaged.

An agitator drive shaft 42 to which the main drive pinion 42a is fixed,is rotatably journaled in bearing sleeves 43 within the motor shaft 24.Said sleeves are slotted to provide one or more oil fiow passages 44.The agitator clutch is advantageously of cone clutch type, the drivingmember 45 of which is fixed to the rotor 23. Cooperating with saidclutch member is a complementary member 46 suitably fastened to theshaft 42. When said clutch members are in engagement shaft 42 will bepower driven, to drive the agitator mechanism during the washing cycle.

The spin clutch drive plate 48 is supported on shaft 42 by a sleeve 41freely rotatable and axially moveable on shaft 42. The complementaryclutch member 5% is secured to the gear casing [4 by means of a flangedcap 5i having any desired plurality of slots 52 through which fingers 53of clutch member extend. By means of a spring 54, clutch member 50 isheld in resilient contact with a brake shoe 55 secured to housing memberl2. During the agitate cycle of operation of the machine, the gearcasing i4 is held against rotation by the brake shoe 55. The drivingclutch member 48 is secured to motor rotor 23 by means including a cap56 directly secured to the rotor as shown, and a flexible bellows 5!having end plates secured to clutch plate 48 and cap 55, in fluid tightrelationship therewith. The bellows operates as an axially extensiblecoupling, and is preferably of metal adequate for transmittingsubstantial torque loads without failure. A spring 58 interposed betweencap 56 and a shoe 59 carried by sleeve 4'! serves to urge said sleeveand thereon secured clutch member 48 downwardly to maintain the clutchparts 48 and 50 in normally disengaged condition.

As presently described, the bellows 5'! is normally full of oil and itis by increasing the oil pressure within the bellows that the clutchparts 48 and 50 are engaged and the gear case l4 connected to the rotorfor rotation of the basket. The bellows is provided with a centrifugallyresponsive valve assembly which will open to relieve the bellowspressure when the motor speed drops toward the stall point. Asatisfactory valve assembly comprises a valve body 56 extending throughthe central web of clutch 48 into the bellows and having an inlet port6! extending through its wall. Advantageously, the valve body is fixedto a mounting plate 62 which is riveted or otherwise suitably secured tothe clutch plate web. An arm 63 extending from the mounting 62 providesa spring anchorage. The valve plug 84 is rotatably housed within thebody 60 and has a passage 65 which, under certain conditions, willregister with the body opening 6| to permit oil to flow out from thebellows into the space between the clutch plates 48 and 5E! whence itwill return to the sump 4|]. The valve plug is actuated by a relativelyheavy arm 66 secured thereto, said arm extending about the bearingsleeve 4'! as shown in Fig. 2. Preferably, the arm is self-weighted,although weights may be applied thereto. The bearing sleeve provides alimiting stop. A spring 6? anchored in the arm 63 and a suitable eyeprovided in the lever 65 tends to return the lever 6t and its associatedvalve plug to the position in which the body port BI and the plugpassage 55 are in registry to permit a free outflow of oil from thebellows. The rotor 23 rotates counterclockwise and as a result, theweighted lever 65 is thrown outwardly by centrifugal force so as towholly or partially misalign the body port 5! and plug passage 65 andeither bleed oil from the bellows or prevent the escape of oiltherefrom, according to the speed of rotation of the clutch plate 48.Suit ably before the stalling speed of the motor has been reached, thevalve will be in full open position. The inertia of the lever 65 is suchthat it will resist return rotation for a moment, despite the urging ofthe spring 67, while the velocity of the clutch plate 48 is decreasing.The deceleration in the rotational velocity of the lever 65, caused bythe deceleration of the clutch plate 48, creates a tangential inertiaforce on the lever 66 urging it to fly outwardly to the position of Fig.3. This tangential inertia force resists the return pull of the spring61 independently of the centrifugal force on the lever 56, whichcentrifugal force may have decreased because of the speed reduction to apoint below that necessary to balance the spring force. Consequently,during deceleration the lever 66 is urged outwardly in opposition to itsspring force, thus damping the reaction to the decreased centrifugalforce. In the same manner a rapid acceleration of the clutch plate 48causes a tangential inertia force on the lever 66 which in this instanceis additive to the spring force in opposing aesnovr 5.. theincreasedcentrifugal force. and thus again dampens-the reaction of the lever tothe velocity change. Since the tangential: inertia forces areproportional to the angular acceleration of the clutch plate 48, theyhave no eifect during periods of constant rotational velocity of theclutch plate and have the greatest effect during rapid changes in therotational velocity. As a consequence the movement of the lever 66 inresponse to velocity changes of the clutch plate 48 lags the changebecause of the effect of the tangential inertia forces during theseperiods of acceleration and deceleration. In other words, the operationof. the valve plug 65 lags behind the increase or decrease of rotationalspeed of clutch plate 48. The operation reduces hunting and tendstosmoothout the operation of the valve and the thereby controlled bellows.

It will be notedthat the entire valve structure, including the mountingplate .62 and the lever 66, is assembled as a unit. Its application tothe clutch plate is greatly facilitated.

The machine is shown in Fig. 1 in the agitating phase of operation. Thesolenoid 39 is de-energized and its valve plug 38 has dropped away fromthe valve port 37. Oil from pump 29 circulates in part through thepassage 36 and the lubrication duct 2| and in part through the orifices35, 3! and and the bore of the valve hub upwardly along the shaft 42into the space it between the clutch plates 55 and 4B, and then throughorifices H and 12 into the bellows 51. The motor operates at high speedduring the agitating cycle and the bleed valve from the bellows will beclosed. However, although the bellows may therefore be substantiallyfull of oil it will not be at a high enough pressure to raise the clutchplate 48 for the reason that a major part of the oil output from pump 29passes through the ports 3| and 31 for return to the sump. This beingthe path of least resistance, it effectively prevents the generation ofoil pressure sufficient either to lift clutch plate 46 out of engagementwith or to raise the clutch plate 48 into engagement with plate 50.Therefore, the shaft 42 is being driven by the motor and the gear casing:4 is at rest on the brake drum 55.

When the operation of the machine is to change over from agitating tospin, a suitable control (not shown) energizes the solenoid 39 to drivethe responsive plunger 35 into seated position on the port 31. Therecirculation of oil from and to the sump 4B is therefore halted and oilwill flow under substantial pressure through the ports 35 and 3| alongthe shaft 42 into the clutch space 10. The size of the orifices 'H issuch that they permit the generation of oil pressure within the space 10to lift the clutch plate 46 (it being understood that this also entailsa vertical movement of the shaft 42) and the shaft is thereby disengagedfrom the motor. The bellows bleed valve is completely closed during theagitating cycle due to motor operation at rated speed; therefore, theoil being confined to the bellows 51, said bellows will immediately riseto the level necessary to lift clutch plate 48 into engagement withplate 50. It will be noted that oil pressure is maintained by flow intothe bellows through ports H and the annular space between the thenseparated clutch plates 45, 46. After a very short slip interval theclutch plate 48 will lift the plate 50 free of the brake drum and thegear casing l4 and its associated spin basket will begin to rotate. Ifthe load of the spin basket causes a drop in motor speed the bleed valvewill open in proportion to the drop and the bellows'will'collapse underthe effect-of spring 58 until the clutch member 50 is lightly in contactwith the brake 55. At this point slippage between plates 48 and 50 willpermit the motor to speed up until the creation of pressure within thebellows again lifts the clutch plate 50. It should be understood thatunder all normalconditions of operation the rotor basket, once it hasstarted to spin will continue to spin, eventhough slowly, for asuflicient interval to permit reclosure of the valve andreactuation ofthe bellows. on

engagement of the respective clutch platesand 50 will increase therotational speed of the basket. and under rated basket loads operationwill quick- 1y reach the point of 'continuedmotor drive. The

bellows operation is rapid and the relatively light engagement of theclutch plate 50 on =the-' brake 55 during bellows retraction andexpansion is therefore of very short duration.

Pressure relief in bellows 51, even though it permits the bellows towithdraw clutch plate 48, does not afiect the operational status of theagitator clutch. Even at stalling speed of the motor, the oil pressuregenerated by the vane pump maintains adequate fluid pressure in thesystem, and the flow through ports "H and between the separated clutchmembers 45 and 46 is relatively so small that the agitator clutch willnot re-engage. It is only when the solenoid is de-energized toreestablish the fluid circuit from and to the sump 48 that pressure willdrop sufliciently to permit re-engagement of the agitator clutch. Such apressure drop will permit spring 58 to drive sleeve 4'! and therewithassociated plate 48 into disengaged position notwithstanding theoperating position of the bleed valve port 65.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. In a rotatable pressure regulator for a fluid system, in combination,a rotatable support plate, a sleeve carried by said plate and spacedfrom the axis of rotation thereof, said sleeve being provided with aport in a side wall thereof, a valve plug rotatably disposed within saidsleeve and provided with a passageway opening to the exterior of saidsleeve at one end and normally communicating with said sleeve port atits other end, and a weighted arm carried by said plug and resilientlybiased to a position contiguous to the axis of rotation and trailingsaid valve plug relative to the direction of rotation of said supportplate, said arm being movable in response to centrifugal force to rotatesaid plug to restrict said sleeve port, the tangential inertia of saidarm damping said valve operation by initially opposing the response ofsaid arm to any change in the centrifugal force acting thereon.

2. In a rotatable fluid pressure control system including a rotatabledisk, a pressure control valve comprising, a sleeve carried by said diskwith the sleeve axis parallel to and displaced from the rotational axis,said sleeve having a port opening in the wall thereof, a valve plugrotatably disposed within said sleeve and provided with a passagewayhaving one end adapted to be aligned with said sleeve port and its otherend opening to a point exterior of said sleeve and plug, a weighted armfixed at one end to said plug, and means biasing said arm toward theaxis of rotation and trailing said valve plu relative to the directionof rotation of said disk, said arm being movable in response tocentrifugal force away from said rotational axis to rotate said plug andthereby restrict said sleeve port, the tangential inertia of said armdamping said valve operation by initially opposing the response of saidarm to any change in the centrifugal force acting thereon.

3. In a rotatable pressure regulator for a fluid system, in combination,a rotatable support plate, a sleeve carried by said plate with thesleeve axis displaced from and parallel to the rotational axis, saidsleeve having a port opening through the side wall thereof, a valve plugrotatably disposed within said sleeve and provided with a passagewayopen to a point exterior of said sleeve at one end and normally alignedwith said sleeve port at its other end, a weighted arm carried by saidplug and trailing said valve plug relative to the direction of rotationof said plate, and spring means biasing said arm toward the axis ofrotation, said arm being movable by centrifugal 8. force away fromretracted position, thereby to rotate said plug and restrict said sleeveport, a. force component on said arm resulting from angular accelerationbeing opposed to said centrifugal force, thereby to damp said valveoperation by initially opposing the response of said arm to any changein angular velocity.

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